Leg extension device



Allg- 13, 1957 H. J. wlLHoYTE LEG EXTENSION DEVICE 2 Sheets-Sheet lFiled NOV. l, 1955 INVENTQR. /owam/ M/hoyfe Aug. 13, 1957 H. J.wlLHoY'n-z 2,802,217

LEG EXTENSION'DEVICE Filed NOV. l, 1955 2 Sheets-Sheet 2 INVENTOR. 76am#/W/og/f? United rates Patent LEG EXTENSION DEVICE Howard J. Wilhoyte,Lafayette, Ind.

Application November 1, 1955, Serial No. 544,156

` V11 claims. (ci. 3 4) This invention relates to a leg extensiondevice, and is adapted particularly for use by persons whose work ortrade involves overhead construction, application or inspection, whichwould ordinarily require the use of a scaffold or elevated platform forefiicient performance. The device is intended to elevate the user asuicient distance above ground or floor level, to bring the users handsand line of vision into close proximity with overhead work to beperformed, without limiting free mobility over the oor, ground, or othersupporting surface. In this respect, the device when applied to theusers leg and foot, presents meritorious advantages over the commonfixed scaffold, elevated platform or ladder generally employed under thecircumstances mentioned. Although the leg extension device is suited foruse by tradesmen as above stated, the use is not to be thusly limited,for as will readily be understood the device might as well be used forentertainment purposes, the picking of fruit, or any of a number ofpursuits wherein the height of the human body is to be extended.

An object of the invention is to provide a leg extension device for thepurposes stated, which is simple, inexpensive, and light of weight. g

Another object is to provide such a device embodying advanced structuralfeatures, which ensure safe and effective manipulation on the part ofthe user, without fatigue and exertion tending to tire the user.

A further object is to incorporate in the leg exten-sion device a systemof articulated links and members yieldingly biased in a particularmanner, to produce what may be considered a supplemental ankle joint, sodesigned and arranged as to impart a natural foot and leg movementdevoid of stiffness or inflexibility conducive of fatigue.

Another object is to incorporate in a device of the character stated,means to compensate or adjust for the weight of the user,'in theinterest of comfort in use by various types of individuals.

The foregoing and other objects are attained by the means describedherein and illustrated upon the accompanying drawings, in which:

Fig. l is a side elevational View of a basic form of the leg extensiondevice, showing the manner of application to the foot and leg of a usersupported upon the device.

Fig. 2 is a side elevational View, parts broken away in the interest ofclarity of illustration, showing a preferred form of the device.

Fig. 3 is a perspective View of 'an-adjustable spring seat, constitutinga detail of the invention.

Fig. 4 is a cross-sectional view taken on line 4 4 of Fig. 2.

Fig. 5 is a perspective view of an equalizer lever, forming a part ofthe invention.

With reference to the simplified form of the device as illustrated byFig. 1, the character 6 indicates a shoe pad upon which is superposedthe shoe 7 of the user. Directly beneath the pad, and spaced therefromin substantial parallelism, is the foot member 8 which is adapted tobear upon the lloor or other surface to be traversed in walking. Theshoe pad and the foot member are maintained in the spaced relationshipillustrated, by means of front and rear upright struts 9 and 10,respectively. Applied to the lower ends 12 of the struts are the hinges13, which serve to pivot the struts upon the foot member 9, so that thestruts may lean forwardly or rearwardly at various angles to the meanplane of the foot member. The upper ends 14 of the struts are connectedto the under face of the shoe pad 6 by means of hinges 15 and 16, whichlikewise permit the struts to lean and change their angular relationshipto the mean plane of the shoe pad. foot member normally form a rightparallelogram the corners of which may change in angularity as the shoepad is shifted forwardly or rearwardly relative to the foot member 8.

A stabilizer or post 17 has an upper end 18 provided with a band orclamp element 19 for embracing the leg of the user, and the lower endportion 20 of this stabilizer may be fixed securely to the rear strut10, so that the strut and the :stabilizer will move and lean in unisonas the wearer uses his foot and leg to manipulate the device. The heightof the stabilizer may be limited, if desired, to the height of the shoe7, and may then have its upper end secured to the side of the shoe abovethe heel 21, as will be understood. The shoe may or may not be xedlymounted upon the pad 6.

By preference, though not of necessity, means may be provided inassociation with the struts, to yieldingly resist forward and rearwardleaning of the struts from the normal vertical position relative to thefoot member 8. Such means may comprise a pair of equalizer springs 22and 23 having inner ends anchored at 24 to a xed and rigid bracket 25,while the outer ends of the springs are anchored as at 26 to the struts9 and 10 intermediate the ends of the struts. The bracket 25 may befixed to the'under surface of the shoe pad 6 as shown, or as an obviousalternative, it may with equal effectiveness and purpose be fixed inupstanding position upon the top face 27 of the foot member. In eithercase, the springs will serve always to bias the struts toward thevertical position.

Thus, in the act of walking there will be a resilient force induced bythe springs 22 and 23, countering any tendency of the struts to lean,forwardly or rearwardly. This actiony of the struts is natural to themovement of the foot in walking, and in cooperation with the bias of thesprings there is achieved a motion simulating ankle movement andlimitation, which is natural and comfortable to the user of the device.By reason of this arrangement of parts, the device of the invention maybe worn for extended periods of time without subjecting the user todiscomfort and fatigue.

To further improve the efliciency and comfort of the device, therearward spring 23 may be made heavier or more resistant to stretchingthan the forward spring 22, so as to more forcefully resist the forwardleaning of the struts. In the case of Fig. l, both springs are tensionsprings as will be understood. In Figs. 2 to 5, the same spring actionis obtained with the use of compression springs, and in addition thespring is rendered adjustable to compensate for differences in theweight or other characteristics of the user. Thus there is suggestedalso the adjustability feature for the Fig. 1 version of the device, ifmaximum comfort and efficiency are considered sufciently important inthe simplied structure of Fig. l.

In principle, the device of Figs. 2 to 5 is similar to Fig. 1 as abovedescribed. Referring to Fig. 2, 30 is the shoe pad and 31 indicates thefoot member. Upstanding upon the foot member is a seriesof perforatedlugs 32 to which Patented Aug. 13, 1957` In other words, the struts, theshoe pad, and thel are pivoted the forward upright struts 33 and therear struts 34. The pivots are indicated `at 35, and may be in the formof bolts, screws, rivets or other types of fasteners. The character 36indicates one or more reinforcing ribs upstanding upon the foot member,which may bev of metal, wood, or other suitable material.

. Depending from the under face of the shoe pad 30 is a series ofperfor-ate lugs 37, tok which are hinged the upper ends Of the struts 33and 34. Suitable pivot members 38 are employed for the purpose. Thepivots and struts are so arranged relative to the shoe pad and the footmember as to form therewith a right parallelogram, which by shifting ofthe shoe pad forwardly and rearwardly, may be distorted to change theangles at the corners thereof. The distortion mentioned is opposed byspring force, as will be explained.

. As shown in Fig. 2, the struts 33--33 and 34-34 are preferably formedof angle members with inwardly projecting legs 39, and such legs of theforward struts 33-33 are spanned by plates such as 4t) and 41, securedto the struts for maintaining the latter in spaced parallelism at alltimes. Similar plates 42 and 43 join and space the rearmost struts .3A-34. The plates may be secured to the struts by means of rivets 44,screws, welds or `any other medium suitable for the purpose, and toimpart added strength to the plates, an end thereof may be turned at anangle as indicated at 45.

The uppermost plates 40 and 42 serve as stops or abutments for a pair ofequalizer levers 46 and 47, which may be in the form of bell cranks asillustrated by Fig. 5, wherein 48 and 49 constitute the arms arrangedsubstantially at right angles to one another. Preferably but notnecessarily, the bell crank may be a composite structure made up of twoidentical stamped plates of metal joined in spaced parallelism by meansof spacing rivets t). Where the arms intersect, the bell crank lever maybe provided with aligned openings 51 adapted to receive `a shaft or pinabout which the lever may be rocked. With further reference to Fig. 5,attention is directed to the notch or socket 52 formed in the undersideof the lever arm 4S, the function of which will be explained presently.

Referring now to Fig. 2, it may be noted that the bell crank lever 46 isquite similar to the lever 47, in that it includes a horizontal arm 53notched at 54, a depending arm 55 corresponding to the arm 49, and anintermediate opening receptive of the pivot member 38 `whereby the bellcrank lever may be rocked about the pivot member.

The primary difference between the bell crank levers 46k and 47, is inthe location of the notches or sockets 52 and 54. The notch or socket 54of bell crank lever 46 is at a greater distance from its pivotalmounting, than is the notch 52 spaced from the pivotal mounting of lever47. The arm 53, therefore, is longer than the arm 48, Fig. 2. lever 46(Fig. 4), may be rather widely spaced apart by the spacers 5S, so thatthe corresponding plates of lever 47 may move between the plates 56-57whenever the levers oscillate about their respective pivot members.rl`he oscillating or rocking of the levers 46 and 47 is induced by theforward and rearward rocking of the struts 33, 34 as the equalizer leverarms 49 and 55 bear against the plates or abutments 40 and 42,respectively.

'l he equalizer lever arms 49 and 5S may be held yieldingly against theabutments 40 and 42 by means of the compression spring 59, the force ofwhich may be adjustable through manipulation of the thumb nut 6i). Thespring surrounds an eye bolt 6l threaded at one end to receive the nut63 ns shown, whereas the remaining end of the bolt carries au eye 62adapted to receive a screw 63 or other suspension means for the eyebolt.

A spring seat member 64, detailed in Fig. 3, transmits the force ofspring 59 to the inner end portions of the arms 53 and 48 at the notches54 and 52, as clearly shown in Fig. The member 64 may carry a pair ofdiametrally Varranged upstanding ribs 65 to engage the notches and Theplates 56--57' constituting the bell crank` thereby preclude dislocationof the spring assembly relative to the bell crank equalizer arms. Fromthe foregoing, it will be understood that any downward displacement ofeither arm 53 or 4S will be yieldingly resisted by the spring 59, to adegree dependent upon the adjustment of thumb nut 60 along the threadedend of the eye bolt 61.

By reason of lthe fact that the force of spring 59 is applied to leverarm 53 at a substantial distance from its fulcrum 38, any clockwisemovement of the bell crank 46 will be quite strongly resisted by thespring. On the other hand, by reason of the shorter length of the arm 48of bell crank 47, any countenclockwise movement of bell crank 47 willmeet with a lesser degree of spring resistance. Accordingly, if the footof the user is applied to the shoe pad 30 and manipulated to lean thepad and struts 33-34 forwardly, or to the right in Fig. 2, the abutmentplate 42 bearing upon the arm 55 of bell crank 46 will lower the leverarm 53 against a substantial resistance set up by spring 59. Conversely,if the foot be manipulated to lean the pad 30 and struts 33-34rearwardly, or to the left in Fig. 2, the other abutment will force thebell crank lever 47 into counterclockwise rotation about its pivot 38,causing the arm 48 to more easily compress the spring 59 due to theshorter length of said arm. As the result of these differential springactions, the natural ankle movements of the user are simulated in theapparatus, enhancing comfort to the user and minimizing fatigue to amost extraordinary degree. Altering the force of spring 59 by means ofthe thumb nut 60, adjusts the device to the weight of individual userswithout altering the ratio of spring pressures acting upon theindividual bell cranks.

To stabilize the device and provide the desired support for the usersankle, a post 67 of wood or other rigid material may be secured to oneof the rearward struts 34, and extended upwardly above the shoe pad 30as shown, so that by means of a band such as 68 the upper end of thepost may be secured to the leg of the user in the manner illustrated byFig. l. The band 68 may be of flexible strap material applied to apart-cylindrical socket member 69 of metal, plastic, or other suitablematerial, xed to the upper end of post 67 by means of screws 70 or otherappropriate fastening devices. The

l flexible strap 68 may be furnished with a buckle or similar fastener,not shown, to hold the users leg in place within the socket member 69.If desired, the upper end of post 67 may be shortened somewhat, andprovided with means for attaching same to the side of the shoe in theregion of the heel cap, as was previously explained in the descriptionof Fig. l.

The post 67 at its lower end 71 may be transversely drilled to receivethe lower bolt or pivot member 35 of strut 34, thereby fixing the postrelative to the strut at that point. At an intermediate point on thepost, a hole 72 may be provided for reception of the upper bolt or pivotmember 38 for strut 34, thereby to anchor the post relative to the strutin the region of the shoe pad 30. A spacer 73 (Fig. 4) may be providedabout the upper bolt 38, between the post 67 andthe adjacent strut 34,to divert the post slightly away from the shoe pad laterally, forproperly positioning the leg socket 69 for comfortable accommodation ofthe users leg. The several openings indicated at 74 in the material ofshoe pad 30, may be provided if desired, to receive screws, bolts, orother fasteners whereby the shoe of the user may be permanently fixed tothe shoe pad. Of course, it may not always be considered desirable to soiix the shoe to the pad, and in such cases the shoe may be moretemporarily applied as by means of straps or clips, for example, asshoesare customarily mounted upon skis or skates.

In conclusion, it may be noted that the device of the invention iscapable of fabrication with the generous use of a light-weight metalsuch as aluminum, with obvious advantage. As shown in Fig. 2, a lift orpad 75 of rubber or similar flexible soft material may be applied to thebotom of the footmember 31, to cushion the step and reduce noise in theuse of the device. Such a pad or lift will be found advantageous alsowhen the device is used in walking upon finished vor polished surfaces,to avoid slipping and any tendency to mar or scratch the surface.

It is to be understood that various modifications and changes instructural details and materials may be resorted to in fabricating thedevice, within the scope of the appended claims, without departing fromthe spirit of the invention.

What I claim is:

1. In a device of the class described, the combination of a horizontalelongated foot member, a horizontal elongate shoe pad, and front andrear substantially vertical struts having upper and lower ends, meanshingedly mounting the upper ends of both struts to the shoe pad andmeans hingedly mounting the lower ends of both struts to the footmember, the hinge means being arranged transversely of the shoe pad andthe foot member, whereby the struts may be inclined forwardly andrearwardly from the vertical in the direction of the major axis of thefoot member, and yielding means operative upon at least one of thestruts opposing inclination of the struts from the substantiallyvertical position.

2. In a device of the class described, the combination of a horizontalelongate foot member, a horizontal elongate shoe pad, and front and rearsubstantially vertical struts having upper and lower ends, meanshingedly mounting the upper ends of both struts to the shoe pad andmeans hingedly mounting the lower ends of both struts to the footmember, the hinge means being arranged transversely of the shoe pad andthe foot member, whereby the struts may be inclined forwardly andrearwardly from the vertical in the direction of the major axis of thefoot member, and yielding means operative upon at least one of thestruts opposing inclination of the struts from the substantiallyvertical position, said yielding means being adjustable as to its forceof opposition.

3. In a device of the class described, the combination of a horizontalelongate foot member, a horizontal elongate shoe pad, and front and rearsubstantially vertical struts having upper and lower ends, transversehinge means on the shoe pad mounting the upper ends of the struts uponsaid pad, other transverse hinge means on the foot member mounting thelower ends of the struts on said foot member, with the struts in asubstantially vertical normal position, yielding means resisting hingingmovement of the struts from the vertical to inclined positions atopposite sides of the vertical, and means associated with said yieldingmeans, to establish a differential between the resistive force opposingmovement of the struts in one direction from the vertical, asdistinguished from the resistive force opposing movement of the strutsin the opposite direction from the vertical.

4. A device in accordance with claim 3, in which the yielding meanscomprises a single compression spring, and means for altering theeffective force of said spring.

5. In a device of the class described, the combination of a horizontalfoot member, a horizontal shoe pad, and front and rear substantiallyvertical struts having upper and lower ends, transverse hinge means onthe shoe pad mounting the upper ends of the struts upon said pad forrocking movement of the struts to forward and rearward inclinations,other transverse hinge means on the foot member mounting the lower endsof the struts on said foot member for rocking movement of the struts toforward and rearward inclinations, an abutment on the front strut, and asecond abutment on the rear strut, said abutments being near the shoepad and arranged transversely thereof, an equalizing lever in the formof a bell crank having a horizontal arm, a depending arm, and anintermediate portion, means pivoting the intermediate portion of theequalizing lever upon the shoe pad, with the depending arm thereofimpinging against the abutment on the rear strut, and the horizontal armthereof extending toward the front strut, a. second equalizing lever inthe form of a bell, crank yhaving a Vhorizontal arm, a depending arm,and an intermediate portion, means pivoting the intermediate yportion ofthe second equalizing lever upon theshoe pad, with the depending armthereof irnpinging against the abutment on the front strut, and thehorizontal arm thereof extending toward the rear strut in substantialparallelism with the horizontal arm of the rst equalizing lever,yielding means operative constantly to urge the horizontal arms of theequalizing levers upwardly toward the shoe p-ad, and a stabilizing postmovable with one of the struts and including an upper end for attachmentto the human body.

6. A device in accordance with claim 5, in which the yielding means actsupon the horizontal arms of the equalizing levers at different distancesfrom the pivotal mountings thereof.

7. A device in accordance with claim 5, in which the combinationincludes means to 'vary the force with which the horizontal arms of theequalizing levers are urged toward the shoe pad by the yielding means.

8. In a device of the class described, the combination of a horizontalfoot member, a horizontal shoe pad, and front and rear substantiallyvertical struts having upper and lower ends, transverse hinge means onthe shoe pad mounting the upper ends of the struts upon said pad forrocking movement of the struts to forward and rearward inclinations,other transverse hinge means on the foot member mounting the lower endsof the struts on said foot member for rocking movement of the struts toforward and rearward inclinations, an abutment on the front strut, and asecond abutment on the rear strut, an equalizing lever in the form of abell crank having a horizontal arm, a depending arm, and an intermediateportion, means pivoting the intermediate portion of the equalizing leverupon the shoe pad, with the depending arm thereof impinging against theabutment on the rear strut, and the horizontal arm thereof extendingtoward the front strut, a second equalizing lever in the form of a bellcrank having a horizontal arm, a depending arm, and an intermediateportion, means pivoting the intermediate portion of the secondequalizing lever upon the shoe pad, with the depending arm thereofimpinging against the abutment on the front strut, and the horizontalarm thereof extending toward the rear strut in substantial parallelismwith the horizontal arm of the first equalizing lever, a threaded roddepending from the shoe pad intermediate the equalizing lever pivots,and passing alongside the horizontal arms of said levers, a compressionspring encircling said rod and having one end abutting the horizontalarms of both equalizing levers, and a nut on the threaded portion of therod abutting the opposite end of the spring, for advancing andretracting the spring relative to said horizontal lever arms.

9. A device in accordance with claim 8, in which the threaded roddepending from the shoe pad, is more distant from the pivot means of thefirst mentioned equalizing iever than from the pivot means of the secondequalizing ever.

10. A device in accordance with claim 8, in which the threaded roddepending from the shoe pad, is located at unequal distances from thepivot means of the first and second equalizing levers, and thecombination includespan upright post movable with the rear strut, saidpost having an upper end projecting above the shoe pad and includingmeans for attachment of the post to a part of the human body.

11. In a device of the class described, the combination of an elongatefoot member, an elongate shoe pad, and front and rear struts havingupper and lower ends, means hingedly mounting the upper ends of bothstruts to the shoe pad and means hingedly mounting the lower ends ofboth struts to the foot member, the hinge means 7 being arrangedtransversely of the shoe pad and the foot extending above the shoe padand including means for member, whereby the struts may be inclinedforwardly attachment to a part of the human body. and rearwardlyrelative to the foot member in the direction of its major axis, to andfrom a right parallelo- References Cmd m the me of this patent gramicform constituted of the hinged shoe pad, the foot 5 UNITED STATESPATENTS member, and the struts, yielding means operative upon the strutswhen inclined as stated, tending to restore the 1613535 Root Jan' 4 1927right parallelogramic relationship of the parts, and an FOREIGN PATENTSupstanding post movable with one of the struts, said post 476,134Germany Apr. 12, 1928

